Merge branches 'fiq' (early part), 'fixes', 'l2c' (early part) and 'misc' into for...

[linux-beck.git] / arch / arm / kernel / entry-header.S

diff --git a/arch/arm/kernel/entry-header.S b/arch/arm/kernel/entry-header.S
index 7b729394e78a30632f059f72aceb82a2660bfe82..4176df721bf09bace95bad96d1c194e5b6b7a038 100644 (file)
--- a/arch/arm/kernel/entry-header.S
+++ b/arch/arm/kernel/entry-header.S
@@ -216,26 +216,49 @@
 #endif
        .endif
        msr     spsr_cxsf, \rpsr
-#if defined(CONFIG_CPU_V6)
-       ldr     r0, [sp]
-       strex   r1, r2, [sp]                    @ clear the exclusive monitor
-       ldmib   sp, {r1 - pc}^                  @ load r1 - pc, cpsr
-#elif defined(CONFIG_CPU_32v6K)
-       clrex                                   @ clear the exclusive monitor
-       ldmia   sp, {r0 - pc}^                  @ load r0 - pc, cpsr
-#else
-       ldmia   sp, {r0 - pc}^                  @ load r0 - pc, cpsr
+#if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_32v6K)
+       @ We must avoid clrex due to Cortex-A15 erratum #830321
+       sub     r0, sp, #4                      @ uninhabited address
+       strex   r1, r2, [r0]                    @ clear the exclusive monitor
 #endif
+       ldmia   sp, {r0 - pc}^                  @ load r0 - pc, cpsr
+       .endm
+
+       @
+       @ svc_exit_via_fiq - like svc_exit but switches to FIQ mode before exit
+       @
+       @ This macro acts in a similar manner to svc_exit but switches to FIQ
+       @ mode to restore the final part of the register state.
+       @
+       @ We cannot use the normal svc_exit procedure because that would
+       @ clobber spsr_svc (FIQ could be delivered during the first few
+       @ instructions of vector_swi meaning its contents have not been
+       @ saved anywhere).
+       @
+       @ Note that, unlike svc_exit, this macro also does not allow a caller
+       @ supplied rpsr. This is because the FIQ exceptions are not re-entrant
+       @ and the handlers cannot call into the scheduler (meaning the value
+       @ on the stack remains correct).
+       @
+       .macro  svc_exit_via_fiq
+       mov     r0, sp
+       ldmib   r0, {r1 - r14}  @ abort is deadly from here onward (it will
+                               @ clobber state restored below)
+       msr     cpsr_c, #FIQ_MODE | PSR_I_BIT | PSR_F_BIT
+       add     r8, r0, #S_PC
+       ldr     r9, [r0, #S_PSR]
+       msr     spsr_cxsf, r9
+       ldr     r0, [r0, #S_R0]
+       ldmia   r8, {pc}^
        .endm
 
        .macro  restore_user_regs, fast = 0, offset = 0
        ldr     r1, [sp, #\offset + S_PSR]      @ get calling cpsr
        ldr     lr, [sp, #\offset + S_PC]!      @ get pc
        msr     spsr_cxsf, r1                   @ save in spsr_svc
-#if defined(CONFIG_CPU_V6)
+#if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_32v6K)
+       @ We must avoid clrex due to Cortex-A15 erratum #830321
        strex   r1, r2, [sp]                    @ clear the exclusive monitor
-#elif defined(CONFIG_CPU_32v6K)
-       clrex                                   @ clear the exclusive monitor
 #endif
        .if     \fast
        ldmdb   sp, {r1 - lr}^                  @ get calling r1 - lr
@@ -269,7 +292,10 @@
        .endif
        ldr     lr, [sp, #S_SP]                 @ top of the stack
        ldrd    r0, r1, [sp, #S_LR]             @ calling lr and pc
-       clrex                                   @ clear the exclusive monitor
+
+       @ We must avoid clrex due to Cortex-A15 erratum #830321
+       strex   r2, r1, [sp, #S_LR]             @ clear the exclusive monitor
+
        stmdb   lr!, {r0, r1, \rpsr}            @ calling lr and rfe context
        ldmia   sp, {r0 - r12}
        mov     sp, lr
@@ -277,6 +303,25 @@
        rfeia   sp!
        .endm
 
+       @
+       @ svc_exit_via_fiq - like svc_exit but switches to FIQ mode before exit
+       @
+       @ For full details see non-Thumb implementation above.
+       @
+       .macro  svc_exit_via_fiq
+       add     r0, sp, #S_R2
+       ldr     lr, [sp, #S_LR]
+       ldr     sp, [sp, #S_SP] @ abort is deadly from here onward (it will
+                               @ clobber state restored below)
+       ldmia   r0, {r2 - r12}
+       mov     r1, #FIQ_MODE | PSR_I_BIT | PSR_F_BIT
+       msr     cpsr_c, r1
+       sub     r0, #S_R2
+       add     r8, r0, #S_PC
+       ldmia   r0, {r0 - r1}
+       rfeia   r8
+       .endm
+
 #ifdef CONFIG_CPU_V7M
        /*
         * Note we don't need to do clrex here as clearing the local monitor is
@@ -290,13 +335,16 @@
        .endm
 #else  /* ifdef CONFIG_CPU_V7M */
        .macro  restore_user_regs, fast = 0, offset = 0
-       clrex                                   @ clear the exclusive monitor
        mov     r2, sp
        load_user_sp_lr r2, r3, \offset + S_SP  @ calling sp, lr
        ldr     r1, [sp, #\offset + S_PSR]      @ get calling cpsr
        ldr     lr, [sp, #\offset + S_PC]       @ get pc
        add     sp, sp, #\offset + S_SP
        msr     spsr_cxsf, r1                   @ save in spsr_svc
+
+       @ We must avoid clrex due to Cortex-A15 erratum #830321
+       strex   r1, r2, [sp]                    @ clear the exclusive monitor
+
        .if     \fast
        ldmdb   sp, {r1 - r12}                  @ get calling r1 - r12
        .else